Tire valve for dual-chambered tires providing for simultaneous but unequal inflationand deflation of said chambers



Jan. 2, 1968 HN ET AL 3,361,153

H. W. K TIRE VAL FOR DUAIJ- MBERED TIRES PROVI G FOR SI TANEOUS BUTUNEQUAL INFLATION A DEFLATION OF SAID CHAMBERS Original Filed Oct. 24,1962 3 Sheets-Sheet 1 INVENTOR. HENRY w. KROHN JOSEPH, .HAWKES FIG. 2 BYMALCOL .ANDERSON RALPH K. BOYER Jan. 2, 1968 H. w. KROHN ETAL 3,361,153-

TIRE VALVE FOR DUAL CHAMBERED TIRES PROVIDING 7 FOR SIMULTANEOUS BUTUNEQUAL INFLATION AND DEFLATION OF SAID CHAMBERS Original Filed Oct. 24.1962 a Sheets-Sheet 2 I I I0 3 4| 44 42 I5 43 r V i ,y K 65 ll FIG.4 V\V x V j is Q I4 fl 74 64 68 7 3 I37 INVENTOR. HENRY w. KROHN JOSEPH s.HA'WKES. y MALCOLM e. ANDERSON RALPH K. BOYER Jan. 2, 1968 H. w. KROHNET AL 3,361153 TIRE VALVE FOR DUAL'CHAMBERED TIRES PROVIDING FORSIMULTANEOUS BUT UNEQUAL INFLATION AND DEFLATION OF SAID CHAMBERSOriginal Filed Oct. 24, 1962 3 Sheets-Sheet 5 FIG. 6

73 FIG. 7

INVENTOR.

9O HENRY W. KROHN JOSEPH S. HAWKES BY MALCOLM G. ANDERSON RALPH K.BOYEIR 3,361,153 Patented Jan. 2, 1868 TIRE VALVE FOR DUAL-CHAMBEREDTIRES PRO- VIDING FOR SIMULTANEOUS BUT UNEQUAL INFLATION AND DEFLATIONOF SAID CHAM- BERS Henry W. Krohn, North Olmsted, and Joseph S. Hawlres,

Cuyahoga Falls, Ohio, Malcolm G. Anderson, Bradenton, Fla., and Ralph K.Boyer, Cleveland, Ohio, assignors to The Goodyear Tire & Rubber Company,Akron, Ohio, a corporation of Ohio Continuation of application Ser. No.232,724, Oct. 24, 1962. This application Nov. 8, 1965, Ser. No. 506,693

13 Claims. (Cl. 137-2345) This application is a continuation of ourapplication Ser. No. 232,724 filed Oct. 24, 1962, now abandoned.

The present invention relates to tires provided with inner and outer airchambers and particularly to tubeless tires provided with such chambers.More specifically, the invention relates to the valve used forsimultaneous inflation of both chambers in a manner to create andmaintain a higher pressure in the inner chamber than in the outerchamber and to the means for releasing excess pressure in the innerchamber.

One object of the invention is to provide a valve for single inflationof both chambers using the same inflation techniques and standardinflation equipment used for inflating a single chamber,

Another object is to provide means for checking the pressure in theouter chamber without releasing air from the inner chamber. The innerchamber pressure may also be checked, if necessary, by using a specialadapter.

Another object is to provide for quick deflation of both chambers.

Another object is to provide means for releasing air from the innerchamber when and if it exceeds a desired predetermined amount.

A more specific object of this invention is to combine the function oftwo valve cores in one whereby the valve core permits inflation of anair chamber and when the air pressure in that chamber builds up beyond apredetermined desired pressure, the valve core will release the excesspressure automatically.

Another object of this invention is to utilize the valve housing as anauxiliary valve to release the pressure in the inner chamber when itbuilds up beyond that desired.

Other objects and advantages of this invention will become apparenthereinafter as the description thereof proceeds, the novel features,arrangements and combinations being clearly pointed out in thespecification as well as the claims thereunto appended.

While the valve is illustrated in connection with a specific safety tireit is to be understood that it may be used with other plural chamberedsafety tires.

In the drawings:

FIG. 1 is a cross-section of a safety tire mounted on a rim and equippedwith a valve made according to this invention;

FIG. 2 is a longitudinal cross-section of the valve means shown in FIG.1;

FIGS. 3 to 7 and 10 inclusive are similar cross-sections of modifiedforms of the valve shown in FIG. 2;

FIG. 8 is a longitudinal cross-section of the outer valve core shown inFIGS. 2 to 7 inclusive; and

FIG. 9 is a longitudinal cross-section of the inner valve core shown inFIG. 6.

In FIG. 1, a tubeless pneumatic tire 1 having beaded edges 2 mounted ona rim 3 forms an air space divided into inner and outer air chambers 4and 5 by means of an inner tire 6 having beaded edges 7 engaging theinner surface of tire 1 adjacent the beaded edges 2 but, as shown, arenot in contact with the rim 3. However, these beaded edges 7 may beconstructed to seat on the rim if desired. Radial grooves 8 are providedin the outer surfaces of beaded edges 7 to provide passages throughwhich air may be supplied to the outer chamber from a valve generallydesignated by the numeral 9. The inner tire 6 is preferablysubstantially inextensible to avoid any material expansion thereof underthe normally higher pressure in the chamber 4 during normal operationand also during emergency operation when the outer chamber 5 is deflatedas by a puncture or blowout of tire 1.

A rubber base 10 having grooves 10 and formed integral with a metal stem11 is attached to the tube 12 in the usual manner. The stem (shown indetail in FIG. 2) has a lateral metering port 13 through which air may.flow to the outer chamber 5 through grooves 10 and 8. It also has anaxial port 14 (FIG. 2) through which air may pass into the inner chamber4. In FIG. 1 the stem is shown provided with an enlarged annular flange15 forming a shoulder engaging theinner surface of the rim 3 around thevalve hole 16 through which the stem 11 extends. A rubber washer 17 onthe stem 11 engages the outer surface of the rim 3 and a nut 18 threadedon threads 19 of the stem 11 is used to compress the rubber washer andseal the stem on the rim in airtight relation thereto. Any suitablesealing means may be employed for this purpose.

Referring now to FIG. 2, it will be noted that inside the stem 11 is ahousing 20 having a flange 21 engaging the outer end of stem 11 and thehousing is releasably held in this position by means of the internallythreaded nut 22 engaging the threads 19 and having a flange 23 overlyingthe flange 21.

The housing 20 has a longitudinal passage 24 extending therethrough fromone end thereof to the other. The outer end of this housing is threadedat 25 to receive the usual valve cap (not shown) and is internallythreaded at 26 to receive the threaded swivel 27 of a valve core 28 ofany desired construction (such as that shown in FIG. 8). The housing 20is sealed to the stem 11 intermediate its ends by an O-ring 29 arrangedin a. groove 30 in the housing.

The inner end of the housing 20 is provided with a lateral port 31 of asize at least equal to that of the port 13 but preferably larger. Thisforms a communication between the passage 32 in the housing 20 and port13. Loosely mounted in passage 32 in the housing 20 is a valve stem 33having flanges 34 for retaining an O-ring 35 therebetween. This O-ring35, in the position shown in FIG. 2, closes the opening 36 formed by areduced portion of the stem 11.

When inflating, the pin 37 of valve core 28 is depressed to allow air toenter the passage 24 and the pressure of the air opens the inner valveto permit air to flow to the inner chamber 4 through port 14 and to theouter chamber 5 through metering port 13. After inflation the pressurein chamber 4 closes the inner valve but port 31 still permits flow ofair between the passage 24 and the outer chamber 5. Thus, it is possibleto check the pressure in chamber 5 by use of a pressure gauge in theusual manner. Such action does not open the inner valve. The pressure inchamber 4 may be measured by removing valve core 28 3 and using a gaugewith a long depressing pin to open the inner valve.

When the inner valve is open the clearance between the O-ring 35 and theenlarged portion 38 in the valve stem determines the rate of air flowthrough the port 14 into the inner chamber 4. The effectivecross-sectional area of the port 14 is determined by the cross-sectionalarea of the space between the O-ring 35 and the opening 38 and is soproportioned with respect to the effective cross-section of the passage13 that air will flow into the inner chamber 4 at a rate such that therewill be a more rapid build-up of the pressure in that chamber than inthe outer chamber 5.

In order to simultaneously deflate both chambers 4 and 5 quickly, thenut 22 is unthreaded from the stem 9 and the housing 20 is bodilyremoved from the stem. Air discharges from the chambers 4 and 5 throughthe ports 14 and 13 respectively. The stem 33 is provided with an upsethead 39 which is larger than the reduced diameter 32 to thus limitmovement of the stem to the left and to provide means whereby, upon theremoval of the housing 20, the stem 33 and the O-ring 35 are constrainedto move therewith leaving the passage 24 through the stem unrestricted.

A relief valve 40 in the base 10 opens at a predetermined differentialpressure to discharge air from the inner chamber 4 to the outer chamber5 if the pressure in the chamber 4 exceeds a predetermined amount. Thiswill build up the pressure in chamber 5 but this pressure is readilyreduced to the desired pressure by depressing the pin 37 so that air mayflow from chamber 5 to the atmosphere. A more detailed description ofthe relief valve 40 and its purpose are more thoroughly described inconnection with FIG. 3.

After mounting the tire 6 and the tube 12 in the tire 1, air isintroduced into the valve to at least partially inflate the innerchamber so as to move the beads of the outer tire I outwardly intoseated position on rim 3. To insure the mounting of the beads of theinner tire 6 against the beads of the outer tire 1, it is recommended todeflate both chambers and reinflate same, during which reinflation theinner tire 6 has an opportunity to adjust itself in symmetrical relationto the outer tire. It is to be noted, however, that if the housing isremoved, air will rush out of the inner chamber and the inner tire willcollapse because the opening 13 is relatively small and air cannotescape from the outer chamber very rapidly. Thus, on reinfiation theremay be a condition where the volumes and/ or pressures of the twochambers are out of proportion. Then, on reinflation, even though theports 13 and 14 are designed to normally give the proper amount of airto both chambers to build up the superior pressure in the inner chamber,it will be noted that on reinflation as air moves into the inner chamberit will expand and compress the air in the outer chamber, raising itspressure quickly, and then as air continues to move into the outerchamber and the inner chamber it is possible that the pressure in theinner chamber may not build up to the desired differential pressure toinsure suflicient seating of the beads 7 of the inner tire 6 on theinner surface of the tire 1. A careful manipulation may avoid this butin FIGURES 3-7 inclusive and 10 it will be noted that the meteringopening is in the housing, whereby as will appear later, the removal ofthe housing permits air to escape rapidly from both chambers. Thus, onreinfiation, the problem of building up the pressure to that desired inthe inner chamber is not a problem.

FIGURES 3-7 inclusive show modifications of the structure illustrated inFIGURE 2, but basically in all of these figures the valve cores arecarried by a housing removably positioned within the stem of the valveso that, for deflation purposes, the housing may be removed to allowfree flow of the air from both chambers. Throughout the drawings similarreference characters refer to similar parts.

A slightly modified form of means for sealing the valve stem to the rimis shown in FIGURES 3, 4 and 5. This means may be used with the valvesshown in FIGS. 6 and 7 where the sealing means is not shown. The rim 3is provided with an opening to receive the valve stem 11 and the stemhas the shoulder 15 abutting against the inside of the rim. A rubberwasher 41 surrounding the stem is compressed against the outer surfaceof the rim by a metal washer 42 when the nut 43, threaded on the stem, iturned to move the washer 42 to the left. In order to prevent excessradial expansion of the thick rubber washer 41, it is provided with ametal band 44 surrounding the rubber Washer at its mid-section. Thisconstruction is illustrative only and is not a part of the presentinvention.

In FIGURE 3, the stem is provided with a housing 45 which house the twovalve cores 28 and 46. The construction of valve core 28 is notimportant and may be of any type, such as shown in FIG. 8. It is usedonly to admit air to the passage 24 or to remove air therefrom. Thevalve core 46 takes the place of the inner valve in FIGURE 2 and isdesigned to accomplish a similar purpose. The valve core 46 comprises astem 47 having an enlarged head 48, a washer 49, loosely mounted on thestern, and at its inner end it is provided with a cup-shaped valve 50having a sealing washer 51 adapted to seat against the inner end 52 ofthe housing 45 when the valve 50 is in closed position as shown in FIG.3. A spring 53 abutting against a shoulder 53 on the inside of thehousing 45 and against the Washer 49 on the pin 47 normally urges thevalve to closed position as shown. This spring 53 is a relatively lowrate spring permitting opening of valve 50 under the pressure of air inthe passage 24 during inflation and it also insures positive return ofthe valve 50 to the position shown in FIGURE 3 when valve 28 closes.Thereafter, it assists in holding the valve 50 closed under the actionof centrifugal force when the tire rotates. The superior pressure of theair in the inner chamber also acts to hold the valve closed. A springsuch as 53 also could be provided for the inner valve in FIG. 2.

A second spring 54 has the ends thereof attached to the enlarged head 48on the pin 47 and to the inner end of the pin 37 forming part of thevalve core 28. This spring is a tension spring and in the position shownin FIG. 3 it is under some tension. During inflation it oflerssubstantially no resistance to the opening of the valve 50, since whenthe pin 37 is depressed during inflation, the spring 54 is actuallyforeshortened and becomes slack. Therefore, the inflation pressure isonly required to overcome the pressure exerted by spring 53. Afterinflation, the spring 54 assists in closing the inner valve 50 since asthe pin 37 moves to the right to closed position, the spring is againdistended and pulls on the stem 47. Note that when valve 28 is opened tocheck the pressure in chamber 5, the valve 50 will remain closed.

In order to seal the housing 45 to the stem, an O-ring 55, mounted in agroove 56 in the housing, abuts the inner Wall of the valve stem 11. Theinner end of the housing is provided with a flat sealing washer 57abutting against a shoulder 58 on the inner end of the valve stem 11.The threaded nut 22 is used to move the housing in a direction tocompress the washer 57 and seal the housing to the stem.

The opposing walls of the stem and housing, washer 57 and O-ring 55 forman air chamber to which air is supplied during inflation from thepassage 24 through the metering port 74 and then through the ports 73into the outer chamber.

The pressure in the inner chamber 4 should exceed by a substantialamount the pressure in the outer chamber 5 in order to maintain thebeads 7 of the inner tire 6 firmly in engagement with the outer tire tothus prevent shifting of the inner and outer tires relative to eachother during normal and emergency operation. However, it is possiblethat the pressure in chamber 4 may build up, as on successivere-inflations for example, to a dangerously high pressure and this maycause a failure of the inner tire 6 either during normal or emergencyoperation. As used herein, the term dilferential pressure means theexcess gauge pressure in the inner chamber over that in the outerchamber. If the pressure in the outer chamber were 24 pounds and thepressure in the inner chamber were 64 pounds, then the differentialpressure would be 40 pounds. Preferably, the minimum differentialpressure should be in the order of 10 to 12 pounds to hold the beads ofthe tires in firm engagement. If 40 pounds is established as the desiredmaximum differential pressure, then means should be provided forrelieving the pressure in chamber 4 When the differential pressureexceeds 40 pounds. To accomplish this, a relief valve 40 is mounted inthe base 10. This comprises a housing 59 provided with any desired valvecore 60 such as that shown in FIG. 8. The housing 59 is threaded into anut 61 molded in the rubber base 14) provided with grooves 10. The valvecore 60 is designed to open when the desired differential pressure isexceeded and discharges air from the inner chamber 4 into the outerchamber 5 through grooves 10 and 8. Thi will increase the gauge pressurein chamber 5 but this may be reduced to the desired pressure by openingvalve 28. While this valve 40 is not shown in FIGS. 4 and 5 it isunderstood such is provided in the base 10 the same as in FIG. 3.

In the form of the invention shown in FIG. 4 instead of using the end 52of the housing 45 as a seat for the valve 51 as in FIG. 3, the innersurface of the housing at 63 is formed with a tapered seat on which isseated a valve core 64 similar to the valve core 28 shown in FIG. 8except that it is provided with a much lower rate spring so that it willpermit opening of the valve under the pressure of the air in passage 24during inflation. This spring performs the same function as the spring53 in FIG. 3. A spring such as 54 shown in FIG. 3, is not shown in FIG.4 or FIG. 5, although one may be provided in these latter figures toprovide an additional holding force to keep the valve closed afterinflation without interfering with normal inflation.

In view of the fact that the core 64 must be mounted from the inside ofthe housing, it is necessary to form the housing of an outer section65'and an inner section 66. When separated, the core 64 is threaded intothe housing section 66. Then, the two sections 65 and 66 are joined toform an integral housing to insure that the two sections cannot bereadily separated and to insure a substantially airtight joint. Core 28may be mounted before or after joining the sections. One way of joiningthe sections is to provide the adjacent ends 67 and 68 with external andinternal threads at 69 to which a bonding cement is applied whereby,after the two housing sections are joined, the bonding cement will holdthemto-gether in airtight relation. These sections may also be united byswaging or by using a press fit or by any other suitable means. Thereason for securing the sections together in this manner is to preventsubstituting an improper core, such as one like core 28 for the valvecore 64, which action Would prevent air entering the inner chamber sincethe core 28 is designed to open only by depressing the pin 37. The outercore 28 may be replaced in the usual manner if it is defective. If theinner valve 64 is defective, a new housing 65-66, equipped with a newvalve 64, must be used and the old one discarded. Note that the housing65-66 is sealed to the stern by the O-ring 55 and the flat washer 57,the same as in FIG. 3.

In FIGURE 5, I have'illustrated the same type of valve as illustrated inFIGURE 4, and the only diflerence is that the housing 65-66 is providedwith a flat washer 70 which abuts against the outer end of the stem 11to seal the outer end of the housing with respect to the stem. The innerend of the housing is provided with a groove 71 in which there is anO-ring 72 engaging the inner adjacent wall of the stem 11 to effect aseal at the inner end of the housing with the stem, the reverse of ,thatshown in FIG. 4.

The dis-advantage of using the sealing means in FIGURE 4 is that, if thenut 22 should become loose, air from the inner chamber may leak past thewasher 57 into the outer chamber to eventually cause an equalization ofthe pressures in the two chambers. This is not desired because undersuch circumstances the beaded edges of the inner tire 6 will not be heldfirmly against the inner walls of the outer tire 4 and the inner tiremay become eccentrically arranged within the outer tire.

Note, however, that with the construction shown in FIGURE 5, if the nut22 loosens enough to destroy the seal effected by the washer 70, noparticular harm is done because even though the housing 65-66 moves tothe right, the O-ring seal 72 will still seal the housing to the stemand no air can leak from the inner chamber unless the movement of thehousing is enough to move the O-ring out of the adjacent reduced portionof the housing. This will maintain the air pressure in the inner chamberand permit operation of the vehicle even though the outer chamberbecomes deflated. It also prevents the collapse of the tire forsubsequent reinflation.

In FIGURES 3, 4 and 5 the metering of the air to the outer chamber isaccomplished in a slightly different man ner than in FIGURE 2. The stemat its inner end is provided with one or more relatively large radialports 73 which permit the air to flow freely to the outer chamber fromthe air compartment formed by the housing 65-66, the stem 11 and thelongitudinally spaced seals 70 and 72 between the housing and stem. Inorder to restrict the amount of air that will flow into the outerchamber, the housing 65-66 in each case is provided with a third ormetering port 74 which is of a restricted cross-section the same as port13 in FIG. 2. The effective cross-sections of the air passages throughcores 64 and 74 should be as specified in connection with ports 14 and13 respectively in FIG. 2. With this arrangement, when it is desired tomount or dismount the tire on a rim, removal of the housing 65-66 fromthe stern provides large openings leading from both chambers to theatmosphere and, therefore, both chambers deflate rapidly. In this waythe disadvantages described in connection. with FIG. 2 are avoided.

' In all of the construction so far described it is apparent. that oninflation, air enters the outer valve 28 and passes through a meteringopening into the outer chamber 5 and the inner valve opens under theinflation pressure and meters the amount of air flowing into the innerchamber. After inflation the inner valve then closes under the higherair pressure in the inner chamber and the influence of the associatedspring if one is used as in FIG. 3. The arrows indicate the flow of airduring inflation.

In order to clearly illustrate the difference between the cores 28 and96 in FIG. 6, their constructions are shown in detail in FIGS. 8 and 9respectively.

The core 28 in FIG. 8 comprises a barrel 75 having the swivel 27externally threaded at 76 for engagement with the threads 26 (FIGS. 2-7)in the valve housing 20 or 65-66. This swivel is rotatably mounted onthe barrel 75 by means of a peripherally extending flange 78 on thebarrel loosely fitting within a groove 79 in the swivel. The pin 37extends through the swivel and barrel and at the inner end has acup-shaped valve 80 crimped at 81 to the pin 37 and provided with arubber or like sealing washer 82. This valve 80 closes the open end. ofthe barrel 75 under the influence of a compression spring 83 having anenlarged end 84 abutting a shoulder on the barrel and an enlargement 85on the pin 37. On depression of the pin 37 by means of an air chuck orthe like, the valve 80 moves to the left and opens the passage throughthe barrel. Exteriorly of the barrel is a sealing washer 86 which isadapted to seat on the tapered seat 87 in the housing 20, 45 or 65-66.

In FIGURES 6 and 9 the inner core 96 comprises a barrel 88 having acylindrical extension 89 rotatably mounted on the barrel 88 in a mannersimilar to the mounting of the swivel 76 on the barrel 75 in FIG. 8. Theouter diameter of the barrel 88 is less than the inner diameter of theinner housing section 66 so that the barrel may slide freely in thathousing. The cylindrical extension is also provided with a boss 90 whichacts as a means for centering a spring 91 which abuts against the innerend of the cup-shaped valve 80 and the extension 89 to urge the taperedsealing washer 92 on the barrel 88 into engagement with the seat 93 onthe housing 65-66, (FIG. 6). The spring 94 acts in a manner similar tothe spring 83 in FIGURE 8, but spring 94 is a lower rate spring designedto permit the cup-shaped valve 80 (FIG. 9) on the stem 37 to open underthe inflation pressure whereby the mere mechanical opening of the valve28 will not open the valve 80 (FIG. 9). Thus, the pressure in the outerchamber 5 may be measured by applying the pressure gauge to the valvestem to open the valve 28 while retaining the air in the inner chamber,since the inner valve is not opened by movement of the outer valve.

The spring 91 (FIG. 6) n the other hand is a heavy spring adapted tohold the barrel 88 of inner valve core on its seat 93 and to permitmovement of the barrel and associated parts off the seat 93 when thedifferential pressure between the chambers 4 and 5 exceeds the springpressure, such as the 40 pounds previously mentioned whereby the air canescape into the passage in the housing and then through the opening 74and 73 into the outer chamber. After the excess pressure is removed fromthe inner chamber, the increased pressure in the outer chamber may berelieved by depressing the pin 37. Actually, as pointed out inconnection with the previously described forms of this invention, thespring 94 may be eliminated and the valve 80 held in closed positionmerely by the air pressure in the inner chamber, but the spring 94 ispreferred to insure positive closing of the valve.

In FIG. 6 the functions of the relief valve 40 and the inner core of themain valve in FIGS. 2-5 inclusive are combined in the inner valve 96made according to FIG. 9 to avoid the added expense of the additionalmaterial and the added labor in applying a valve such as 40. Thecritical feature of the invention shown in FIG. 6 is in utilizing thevalve barrel 88 as a relief valve so that it functions to let air out ofthe inner chamber when that inner chamber pressure exceeds the desiredpressure differential. For this purpose, the cylindrical extension 89 isnot provided with threads but instead is made smooth as is the adjacentsurface of the housing section 65-66 and its diameter is sufficientlyless than the inner diameter of the housing to provide a clearance space97.

It must be borne in mind that excessive differential pressure may causethe inner tire to fail. Therefore, if the inner chamber gauge pressureis 64 pounds and the outer chamber gauge pressure is 24 pounds, there isonly a differential pressure of 40 pounds between the two chambers andthe inner tire would not be subjected to any greater rupturing forceduring normal operation than if the gauge pressures in the two chamberswere at a lower level but still at the same differential pressure.

In case of a blowout or a puncture, air is discharged from the outerchamber. This decreases the gauge pressure in chamber 5 to thus increasethe differential pressure between the two chambers 4 and 5 and when themaximum differential pressure is exceeded, air escapes from the innerchamber into the outer chamber 5 and from this chamber the air passesout of the tire through the puncture or the opening formed by theblowout.

Assuming the gauge pressure in the inner chamber is 64 pounds, and thatin the outer chamber is 24 pounds, it is obvious that a blowout willsuddenly release the air from the outer chamber and the inner tire 6will be subjected to 64 pounds of pressure until the relief valve opensand drops the gauge pressure therein to that of the differentialpressure of 40 pounds. The differential pressure should be preferablymore than the normal gauge pressure in the outer chamber so that underrun flat conditions with the inner tire carrying the load the beads 7 oftire 6 will be held firmly against the outer tire 1 and prevent theinner tire becoming eccentrically arranged within the outer tire. Thisalso insures stability to the outer tire. It also insures a greaterrolling radius because of the higher pressure. It is obvious that adifferential pressure of 15 pounds might not be sufficient under runfiat conditions although it may be sufficient under normal conditionswhen the inner tire is not carrying the load. Frequently, along todayssuperhighways, it is dangerous to try to stop and make such a repair orchange along the highway and in places it is prohibited. On some roadsit is impossible to find a sufficient shoulder to conveniently make sucha change or repair.

In order to insure that the continued operation of the vehicle may be atleast a fair rate of speed and even normal speed, it is desirable toplace a lubricant within the chamber 5 so as to lubricate the contactingwalls of the inner and outer tires under emergency conditions. Such alubricant should be non-compatible with the surfaces of the outerchamber so that it will be always ready to act as a lubricant if ablowout or puncture occurs.

In FIG. 7 the inner valve core 96' is similar to core 96 in FIG. 6. Thevalve barrel 98 thereof is similar in construction and function to thebarrel 88 in FIG. 9. The only change is in the contours of the barreland its seating arrangement in the housing. Note that the housing 65-66is provided with a relatively narrow, axially extending annular seat 99at one end of the reduced opening 100 of the housing. The barrel isprovided with a rubber seal formed by a cylindrical part 101 surroundingthe barrel 98 and a radially flanged portion 103 which abuts against theaxially extending seat 99. A flange 104 on the barrel acts as a back-upmember for the flanged portion 103 of the rubber washer. The operationof this valve core 96 is the same a valve core 96 shown in FIG. 6, butit is to be noted that since there is no wedging action of the portion103 on the barrel and the seat 99 on the housing the valve barrel 98will move off its seat more uniformly than in FIG. 6 since the seat onthe housing and the tapered sealing washer on the barrel as in FIG. 6may bind and require a greater differential pressure to unseat thebarrel.

In FIG. 7, the spring 91 abuts against a shoulder 105 formed by areduced portion of the housing whereby removal of the valve 28 from thehousing will not release the spring pressure of spring 91 and air willnot be released from the chamber 4. Nor will the spring 91 have a chanceto fall out of the passage in the housing. In FIG. 6 this could happenand not be noticed. Then when valve 28 is replaced, the inner valve willnot function. In FIG. 7 the spring 91 must be assembled when the twosections 65 and 66 of the housing are being assembled. The spring isplaced in the inner section 66 of the housing and then the other section65 is assembled by threading the two sections together. Thus, if thevalve core 28 is then removed, the spring 91 will remain in place.

While it is possible in a construction of this kind to provide asectional housing 65-66 in which the two sections may be separated forreplacement of the inner valve core, such permitted replacement is notdesirable since a valve core of the wrong spring pressure may be used asa replacement.

In the modification shown in FIG. 10 the stem 11 is provided with athree-part housing to take the place of the housings 65-66 in FIGS. 4-7inclusive. The tubular sections 106 and 107 have annular seats 108 and109 embraced by the annular ends 110 and 111 respectively of a bellowstype compression spring 112 which urges the sections 106 and 107 awayfrom each other. The inner end of section 106 is provided with rubberwasher 113 cemented thereto or (as shown) provided with a lip 114 fittedin a groove 115 in the housing. An annular seat 116 formed at the innerend of the stem is engaged by the rubber washer 113 to seal the housingto the stem at its inner end.

The outer end of section 107 may be for-med as shown in FIG. and sealedto the stem 11 as in FIG. 5 by use of a nut 22 and flat washer 70. Theoverall length of the housing when the spring is relaxed is sufficientlylong to protrude beyond the stern when the washer 113 engages the seat116, whereby when a nut 22 such as in the other figures is screwed downinto sealing position the sections 106 and 107 move toward each otherand com-press the spring 112 sufliciently to hold the seal 113 on theseat 116 with a pressure sufiicient to overcome the differentialpressure between the chambers until the dilierential pressure in theinner chamber 4 reaches the maximum differential pressure desired, afterwhich the inner housing 106 is caused to move toward section 107 againstthe action of spring 112 and thus permit air to pass from the innerchamber around the housing section 106 to the large openings 117 in thestern and the metering opening 118 in the housing. Thereafter, thepressure in the chamber 5 above that desired may be relieved by openingthe valve in the outer core 28 as described with reference to the otherforms of the invention. The inner housing 106 has a core 64 the same asin FIGS. 4 and 5 to permit air to enter the inner chamber duringinflation. The sections 106 and 107 may be provided with enlargedguiding flanges 119 and 120 respectively or the sections may have asufiicient outer diameter to have a loose sliding fit in the stem tothus avoid lateral flexing strains on the spring 112.

The inner end of the stem is provided with threads 121 into which oneend of a fishing tool (not shown) may be threaded. Such a tool isattached to the valve to pull the valve through a hole in a rim and isusually threaded on the threads 25 for the valve cap. However, due tothe fact rim holes are small and the present valve is of necessitylarger in diameter than standard valves, the threaded portion must be onthe inside to permit the valve to be withdrawn from the hole. Thehousing is first removed and fishing tool would then be threaded inplace. Such a tool generally employs a flexible cord or chain which isfirst manually inserted through the rim hole from the inside as is wellunderstood in the art. Similar threads may be provided in the otherforms of the invention illustrated.

Essentially in all FIGS. 1-7 and there are three valves for controllingthe pressures in the chambers and in FIGS 1-5 inclusive these areseparate structures. These valves will be referred to as the first valvesuch as 2-8, for controlling the flow of air into and out of saidhousing; the second inflation valve such as 64 for controlling the flowof air between said housing and inner chamber and the third valve suchas 40 for discharging air from the inner chamber when the differentialpressure is exceeded. In FIGS. 6 and 7, however, while the first valveis separate, the second valve is combined in a single valve core withthe third valve, and in FIG. 10 the portion 106 of the housing acts asthe relief valve. Their operations, however, are somewhat different thanthe corresponding valves in FIGS. 1 through 5. In FIGS. 6, 7 and 10 thethree valves are all mounted on the stem and all three are removablewith the housing, whereas in FIGS. 15' inclusive the relief valve 40 isfixed in the base 10 and is not removable with the housing.

It is desirable to maintain the flow of air through ports 14 and 74 inthe same proportion regardless of the air line pressure used since awide variance in the air line pressures may cause a wide variance in theproportionate flow of air to the chambers due primarily to the fact thatthe air supplied to the port 14 travels in substantially a straight pathand the air supplied to the port 74 must change direction in order tomove laterally through port 74. In order to accomplish this result, FIG.5 shows a wall 121' in the housing having a metering opening 122' torestrict the flow of air from the supply line so that the resultingpressure in the housing inwardly of the restricted passage is somewhatthe same for different air line pressures. Of course, any excesspressure in the inner chamber will be automatically relieved by therelief valve 40, but it is entirely possible that the restricted opening122' may be made of a size to so control the flow of air into the innerend of the housing that the relief valve 40 may be eliminated. The sizeof the opening 122' may be in the order of .030 to .050 inch.

Essentially in all forms of the invention the housing and the stemtogether with the sealing means between the housing and the stem form anair compartment to which air is supplied through the port 31 (FIG. 2),the port 74 (FIGS. 3 to 7), or port 118 (FIG. 10) in the housing. Thechamber 5 is supplied with air from said compartment through therespective metering ports 73, 13 and 117 of the other figures. The portsin the stems at the inner ends thereof supply air to the inner chamberfrom the housing when the inner valves are open. When one of the innervalves is closed, it seals off communication between the inner and outerchambers. This permits checking the pressure in the outer chamberwithout releasing any air from the inner chamber.

In the claims the terms outer end and inner end as applied to the endsof the stem or housing are respectively the right and left ends thereofas viewed in the drawings.

When the term port is used in the claims, this term is to be understoodas including a plurality of ports having the function and combinedcross-sections substantially the same as that of a single port suitablefor the purposes specified.

While certain representative embodiments and details have been shown forthe purpose of illustrating the invention, it will be apparent to thoseskilled in the art that various changes and modifications may be madetherein without departing from the spirit or scope of the invention.

We claim:

1. In combination, a tire having inner and outer chambers, valvemechanism for inflating said chambers comprising a hollow valve stemhaving a first port for communicating with said outer chamber and asecond port for communicating with said inner chamber, a housingremovably mounted in said stem having: a longitudinal air passagetherethrough and provided with a metering port in open communicationwith said first port to permit free flow of air from said passage to andthrough said first port, longitudinally spaced sealing means between theadjacent walls of said stem and housing for sealing the spacetherebetween at opposite sides of said first and metering ports, anormally closed first valve on said housing at the outer end of saidpassage in said housing openable to permit air from a source of airunder pressure to enter said passage, a second valve mounted on saidhousing at the inner end of said passage which, when closed, cuts offcommunication between said passage and said second port and when openplaces said inner chamber and passage in said housing in opencommunication and controls the flow of air therebetween, said secondvalve being movable to open position by a force exerted. thereonsuperior to the force holding said valve closed, said latter force atleast in part including the force created by the pressure of the air inthe inner chamber, said second valve additionally, when closed,completely cutting olf communication between said first and secondports, said first and second valves being independently operable wherebythe normal opening or closing of said first valve will not actuate saidsecond valve, both of said valves being mounted in said housing andbodily removable therewith from said stem to permit rapid deflation ofsaid outer chamber through said first port, said metering port having across-section substantially smaller than that of said first port tometer the flow of air to and through said first port, the effective sizeof said metering port being such as to meter the rate of flow of air tothe outer chamber, as compared to the fiow of air to the inner chamberwhen said second valve is open, that the pressure in the inner chamberwill build up substantially faster than that in the outer chamber andwill be maintained at such higher pressure after inflation by theclosing of said second valve, and a third valve between said inner andouter chambers constructed to automatically open and release air fromsaid inner chamber to said outer chamber if and when the pressure insaid inner chamber exceeds, by a predetermined amount, the pressure insaid outer chamber, said third valve being mounted within said stem.

2. The combination as set forth in claim 1 in which said third valve ismounted on said housing.

3. The combination as set forth in claim 1 in which said third valve ismounted on said housing at its inner end and said second valve ismounted on said third valve, with each being independently operable fortheir respective purposes.

4. Valving mechanism comprising a hollow valve stem having first andsecond ports adapted to communicate respectively with the outer andinner chambers of a tire when used therewith, a tubular housing, havinga longitudinal passage therethrough, removably mounted in said stem andhaving at least a portion of its outer wall adjacent the inner wall ofsaid stern spaced from said inner wall in the vicinity of said firstport when mounted in said stem, sealing means between the outer wall ofsaid housing and the inner wall of said stem at longitudinally spacedpositions at opposite sides of said first port to form an air chamberwith the adjacent walls of said stem and housing, a metering third portin a lateral wall of said housing of a cross-section substantiallysmaller than the cross-Section of said first and second ports andcommunicating with said passage in said housing and with said airchamber to determine the flow of air into said chamber and through saidfirst port while said housing is in said stem, a normally closed firstvalve in the outer end of said housing openable to permit flow of airunder pressure into and out of said passage, a second valve mounted insaid passage at the inner end of said stem, which, when closed, cuts offcommunication between said passage and second port, said first andsecond valves being mounted for movement to open and closed positionsindependently of each other, said second valve being openable by a forceexerted thereon superior to the force holding said second valve closedas by the force created by air under pressure supplied to said housingduring infiation, said housing with said valves being removable as aunit from said stem to provide open communication of said first andsecond ports with the atmosphere and said first and second ports havinga relationship of flow area selected to provide that when said valveshave been removed from the stem as a unit and air is exhausting fromsaid outer and inner chambers simultaneously the flow of air from saidinner chamber is at a rate such that collapsing of said inner chamberwill not occur, and means for removably holding said housing in position within said stem.

5. Valving mechanism as set forth in claim 4 wherein said second valveis irremovably mounted in said housing while said housing is intact.

6. Valving mechanism as set forth in claim 4 wherein the tubular housingis initially formed as separate inner and outer sections to permitmounting of said second valve in said inner section and then assembledand sealed together to make a substantially permanent unitary housingenclosing said second valve within the walls of said tubular stem tothus prevent removal of said second valve from said housing while thelatter is intact.

7. Valve mechanism as set forth in claim 4 in which a spring isconnected between said first and second valves to constitute anadditional closing force for said second valve and being so connected tosaid first valve that when said first valve is opened the closing forceof said spring lessens and when said first valve closes said springagain becomes operative to provide said additional closing force forholding said second valve in closed position.

8. Valve mechanism as set forth in claim 4 in which said stem isprovided with a radially extending, axially facing seat adjacent itsinner end opposed to the inner end of said housing, and in which one ofsaid sealing means is a compression seal arranged between said seat andthe inner end of said housing when said housing is retained therein bysaid holding means, and the other of said seals is an O-ring sealarranged adjacent the outer end of said housing in slidable engagementwith the inner wall of said stem.

9. In combination, a tire having inner and outer chambers, valvemechanism for inflating said chambers comprising a stern having a firstport for supplying air to the outer chamber, a second port in said sternfor supplying air to the inner chamber, a housing mounted in said stem,longitudinally spaced sealing means between said stem and housing atopposite sides of said first port, a port in said housing in opencommunication with said first port in said stem, a first valve in theouter end of said housing for admitting air to and for permittingremoval of air from said chambers, a second valve at the inner end ofsaid housing for admitting air into said inner chamber on inflation andfor releasing air from said inner chamber when the pressure of the airin the inner chamber exceeds a predetermined differential pressure withrespect to the pressure in the outer chamber, said second valvecomprising a valve barrel, a seat in said housing engageable by saidbarrel to close the passage through said housing, a spring mounted insaid housing normally urging said barrel against said seat in saidhousing against the pressure of the air in the inner chamber, saidbarrel having a third valve mounted therein and openable to admit air tosaid inner chamber through said barrel under a suflicient air pressurein said housing to open the latter valve against the force holding saidlatter valve closed and independently movable with respect to said firstvalve, said spring yielding under a predetermined pressure in said innerchamber in excess of that in said housing to move said barrel off itsseat and permit air to escape from said inner chamber around saidbarrel.

10. The combination as set forth in claim 9 in which said barrel has atapered seat engaging the seat on said housing provided for said barrel.

11. The combination as set forth in claim 9 in which the seat on saidhousing comprises an axially facing seat and the valve barrel isprovided with a seal having an axially facing seat engageable with saidaxially facing seat on said housing.

12. In combination, a tire having inner and outer chambers, valvemechanism for inflating both said chambers comprising a hollow sternhaving a first port for admitting air to the outer of said chambers anda second port for admitting air to the inner one of said chambers, ahousing in said stern having a passage therethrough, a valve mechanismfor controlling the flow of the air into said inner chamber through saidsecond port and for releasing air therefrom when the pressure in saidchamber exceeds that in said outer chamber by a predetermined amount,comprising a seat on said housing, a barrel in said housing adapted toengage the seat on said housing, a valve mounted in said barrel, and aspring for normlly urging said barrel against its seat, said valve insaid barrel being openable to admit air to said inner chamber when thepressure in said housing is suflicient to overcome the pressure holdingthat valve closed and said barrel being movable off its seat to releaseair from said inner chamber when the pressure in said inner chamber isin excess of the desired pressure therein.

13. The combination as set forth in claim 12 in which there is a secondspring normally biasing said valve to closed position against said seatin said housing, said first and second springs acting in a direction tourge said valves and barrel respectively in opposite directions to thuscontrol the flow of air into and out of the chamber supplied by one ofsaid ports in said stem, the valve in said barrel permitting the flow ofair into said chamber and the barrel being releasable from its seat topermit flow of air out of said chamber by a pressure in that chambersuperior to the pressure holding said barrel on 10 its seat.

References Cited UNITED STATES PATENTS Eckenroth 152-342 X Creamer277-2O Gramelspacher 152-342 Steer 1.37--234.5 Anderson et al. 152--427X WILLIAM F. ODEA, Primary Examiner.

D. LAMBERT, Assistant Examiner.

1. IN COMBINATION, A TIRE HAVING INNER AND OUTER CHAMBERS, VALVEMECHANISM FOR INFLATING SAID CHAMBERS COMPRISING A HOLLOW VALVE STEMHAVING A FIRST PORT FOR COMMUNICATING WITH SAID OUTER CHAMBER AND ASECOND PORT FOR COMMUNICATING WITH SAID INNER CHAMBER, A HOUSINGREMOVABLY MOUNTED IN SAID STEM HAVIHNG A LONGITUDINAL AIR PASSAGETHERETHROUGH AND PROVIDED WITH A METERING PORT IN OPEN COMMUNICATIONWITH SAID FIRST PORT TO PERMIT FREE FLOW OF AIR FROM SAID PASSAGE TO ANDTHROUGH SAID FIRST PORT, LONGITUDINALLY SPACED SEALING MEANS BETWEEN THEADJACENT WALLS OF SAID STEM AND HOUSING FOR SEALING THE SPACETHEREBETWEEN AT OPPOSITE SIDES OF SAID FIRST AND METERING PORTS, ANORMALLY CLOSED FIRST VALVE ON SAID HOUSING AT THE OUTER END OF SAIDPASSAGE IN SAID HOUSING OPENABLE TO PERMIT AIR FROM A SOURCE OF AIRUNDER PRESSURE TO ENTER SAID PASSAGE, A SECOND VALVE MOUNTED ON SAIDHOUSING AT THE INNER END OF SAID PASSAGE WHICH, WHEN CLOSED, CUTS OFFCOMMUNICATION BETWEEN SAID PASSAGE AND SAID SECOND PORT AND WHEN OPENPLACES SAID INNER CHAMBER AND PASSAGE IN SAID HOUSING IN OPENCOMMUNICATION AND CONTROLS THE FLOW OF AIR THEREBETWEEN, SAID SECONDVALVE BEING MOVABLE TO OPEN POSITION BY A FORCE EXERTED THEREON SUPERIORTO THE FORCE HOLDING SAID VALVE CLOSED, SAID LETTER FORCE AT LEAST INPART INCLUDING THE FORCE CREATED BY THE PRESSURE OF THE AIR IN THE INNERCHAMBER, SAID SECOND VALVE ADDITIONALLY, WHEN CLOSED, COMPLETELY CUTTINGOFF COMMUNICATION BETWEEN SAID FIRST AND SECOND PORTS, SAID FIRST ANDSECOND VALVES BEING INDEPENDENTLY OPERABLE WHEREBY THE NORMAL OPENING ORCLOSING OF SAID FIRST VALVE WILL NOT ACTUATE SAID SECOND VALVE, BOTH OFSAID VALVES BEING MOUNTED IN SAID HOUSING AND BODILY REMOVABLE THEREWITHFROM SAID STEM TO PERMIT RAPID DEFLECTION OF SAID OUTER CHAMBER THROUGHSAID FIRST PORT, SAID METERING PORT HAVING A CROSS-SECTION SUBSTANTIALLYSMALLER THAN THAT OF SAID FIRST PORT TO METER THE FLOW OF AIR TO ANDTHROUGH SAID FIRST PORT, THE EFFECTIVE SIZE OF SAID METERING PORT BEINGSUCH AS TO METER THE RATE OF FLOW OF AIR TO THE OUTER CHAMBER, ASCOMPARED TO THE FLOW OF AIR TO THE INNER CHAMBER WHEN SAID SECOND VALVEIS OPEN, THAT THE PRESSURE IN THE INNER CHAMBER WILL BUILD UPSUBSTANTIALLY FASTER THAN THAT IN THE OUTER CHAMBER AND WILL BEMAINTAINED AT SUCH HIGHER PRESSURE AFTER INFLATION BY THE CLOSING OFSAID SECOND VALVE, AND A THIRD VALVE BETWEEN SAID INNER AND OUTERCHAMBERS CONSTRUCTED TO AUTOMATICALLY OPEN AND RELEASE AIR FROM SAIDINNER CHAMBER TO SAID OUTER CHAMBER IF AND WHEN THE PRESSURE IN SAIDINNER CHAMBER EXCEEDS, BY A PREDETERMINED AMOUNT, THE PRESSURE IN SAIDOUTER CHAMBER, SAID THIRD VALVE BEING MOUNTED WITHIN SAID STEM.